scholarly journals A Rare p.T599dup BRAF Mutant NSCLC in a Non-Smoker

2020 ◽  
Vol 28 (1) ◽  
pp. 196-202
Author(s):  
Alla Turshudzhyan ◽  
James Vredenburgh
Keyword(s):  
Lung Cancer ◽  
Targeted Therapies ◽  
Kinase Activity ◽  
Mitogen Activated Protein Kinase ◽  
Braf Mutations ◽  
Activating Mutations ◽  
Extracellular Signal ◽  
Activating Mutation ◽  
Mitogen Activated Protein ◽  
Murine Sarcoma

V-RAF murine sarcoma viral oncogene homolog B1 (BRAF) mutated non-small-cell lung cancer (NSCLC) is an exceptionally rare form of lung cancer, found only in one to two percent of patients with an NSCLC diagnosis. BRAF NSCLC traditionally affects former or active smokers. BRAF mutations have always been of special interest to the oncological community, as they offer potential for targeted therapies. BRAF mutation spectrum includes mutations that are of both V600 and non-V600 types. BRAF V600 is an activating mutation, which results in high kinase activity and overproduction of active oncoproteins such as rapidly accelerated fibrosarcoma (RAF). This makes them susceptible to targeted therapies with RAF inhibitors. There has been little evidence, however, regarding efficacy of RAF inhibitors towards non-activating mutations that have intermediate to low kinase activity, such as non-V600 BRAF mutations. While several approaches have been investigated to overcome the limitations of RAF inhibitors, such as use of mitogen-activated protein kinase kinase (MEK) and extracellular signal-regulated kinase (ERK) inhibitors or combination of MEK and RAF inhibitors, none of them have been proven to have a superior efficacy for low kinase activity non-V600 BRAF tumors. We present a case of an extremely rare variant of NSCLC BRAF p.T599dup mutation in a non-smoker that responded to a targeted combination therapy with RAF and MEK inhibitors. The patient responded well to therapy that usually targets high kinase activity V600 mutations. Our hope is to bring more attention to non-V600 mutations and document their responses to existing and new therapies.

scholarly journals EGF stimulates gastrin promoter through activation of Sp1 kinase activity

2000 ◽  
Vol 278 (4) ◽  
pp. C697-C708 ◽  
Author(s):  
Sergey Chupreta ◽  
Ming Du ◽  
Andrea Todisco ◽  
Juanita L. Merchant
Keyword(s):  
Kinase Activity ◽  
Egf Receptor ◽  
Solid Phase ◽  
Receptor Activation ◽  
Mitogen Activated Protein Kinase ◽  
Kinase Assay ◽  
Ags Cells ◽  
Extracellular Signal ◽  
Mitogen Activated Protein

Epidermal growth factor (EGF) receptor activation stimulates gastrin gene expression through a GC-rich element called gastrin EGF response element (gERE). This element is bound by Sp1 family members and is a target of the ras-extracellular signal-regulated kinase (Erk) signal transduction cascade. This raised the possibility that Sp1 may be phosphorylated by kinases of this signaling pathway. Erk is capable of phosphorylating other mitogen-inducible transcription factors, e.g., Elk and Sap, suggesting that Erk may also mediate EGF-dependent phosphorylation of Sp1. This possibility was tested by studying Sp1-dependent kinase activity in extracts prepared from EGF-activated AGS cells by use of solid-phase kinase assays and immunoprecipitation of metabolically labeled Sp1. The results revealed that Sp1 kinase activity (like gastrin promoter activation) is inhibited by PD-98059 and, therefore, is dependent on mitogen-activated protein kinase kinase 1 (Mek 1). However, EGF-dependent activation of endogenous Erk did not account for most of the Sp1 kinase activity, since Erk and additional Sp1 kinase activity analyzed in a solid-phase kinase assay eluted from an ion-exchange column in different fractions. Phosphoamino acid analysis of in vivo radiolabeled Sp1 demonstrated that the kinase phosphorylates Sp1 on Ser and Thr in response to EGF. Therefore, most EGF-stimulated Sp1 kinase activity is Mek 1 dependent and distinct from Erk.

scholarly journals MEK-1 phosphorylation by MEK kinase, Raf, and mitogen-activated protein kinase: analysis of phosphopeptides and regulation of activity.

1994 ◽  
Vol 5 (2) ◽  
pp. 193-201 ◽  
Author(s):  
A M Gardner ◽  
R R Vaillancourt ◽  
C A Lange-Carter ◽  
G L Johnson
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Peptide Mapping ◽  
Mitogen Activated Protein Kinase ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Regulation Of Activity ◽  
Mek Kinase ◽  
Mutant Kinase

MEK-1 is a dual threonine and tyrosine recognition kinase that phosphorylates and activates mitogen-activated protein kinase (MAPK). MEK-1 is in turn activated by phosphorylation. Raf and MAPK/extracellular signal-regulated kinase kinase (MEKK) independently phosphorylate and activate MEK-1. Recombinant MEK-1 is also capable of autoactivation. Purified recombinant wild type MEK-1 and a mutant kinase inactive MEK-1 were used as substrates for MEKK, Raf, and autophosphorylation. MEK-1 phosphorylation catalyzed by Raf, MEKK, or autophosphorylation resulted in activation of MEK-1 kinase activity measured by phosphorylation of a mutant kinase inactive MAPK. Phosphoamino acid analysis and peptide mapping identified similar MEK-1 tryptic phosphopeptides after phosphorylation by MEK kinase, Raf, or MEK-1 autophosphorylation. MEK-1 is phosphorylated by MAPK at sites different from that for Raf and MEKK. Phosphorylation of MEK-1 by MAPK does not affect MEK-1 kinase activity. Several phosphorylation sites present in MEK-1 immunoprecipitated from 32P-labeled cells after stimulation with epidermal growth factor were common to the in vitro phosphorylated enzyme. The major site of MAPK phosphorylation in MEK-1 is threonine 292. Mutation of threonine 292 to alanine eliminates 90% of MAPK catalyzed phosphorylation of MEK-1 but does not influence MEK-1 activity. The results demonstrate that MEKK and Raf regulate MEK-1 activity by phosphorylation of common residues and thus, two independent protein kinases converge at MEK-1 to regulate the activity of MAPK.

scholarly journals Phosphorylation of TPL-2 on Serine 400 Is Essential for Lipopolysaccharide Activation of Extracellular Signal-Regulated Kinase in Macrophages

2007 ◽  
Vol 27 (21) ◽  
pp. 7355-7364 ◽  
Author(s):  
M. J. Robinson ◽  
S. Beinke ◽  
A. Kouroumalis ◽  
P. N. Tsichlis ◽  
S. C. Ley
Keyword(s):  
Kinase Activity ◽  
Mitogen Activated Protein Kinase ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Control Step ◽  
Cytokine Tumor Necrosis Factor ◽  
Mek Kinase ◽  
Lps Activation ◽  
Stimulation Of

ABSTRACT Tumor progression locus 2 (TPL-2) kinase is essential for Toll-like receptor 4 activation of the mitogen-activated protein kinase extracellular signal-regulated kinase (ERK) and for upregulation of the inflammatory cytokine tumor necrosis factor (TNF) in lipopolysaccharide (LPS)-stimulated macrophages. LPS activation of ERK requires TPL-2 release from associated NF-κB1 p105, which blocks TPL-2 access to its substrate, the ERK kinase MEK. Here we demonstrate that TPL-2 activity is also regulated independently of p105, since LPS stimulation was still needed for TPL-2-dependent activation of ERK in Nfkb1 −/− macrophages. In wild-type macrophages, LPS induced the rapid phosphorylation of serine (S) 400 in the TPL-2 C-terminal tail. Mutation of this conserved residue to alanine (A) blocked the ability of retrovirally expressed TPL-2 to induce the activation of ERK in LPS-stimulated Nfkb1 −/− macrophages. TPL-2S400A expression also failed to reconstitute LPS activation of ERK and induction of TNF in Map3k8 −/− macrophages, which lack endogenous TPL-2. Consistently, the S400A mutation was found to block LPS stimulation of TPL-2 MEK kinase activity. Thus, induction of TPL-2 MEK kinase activity by LPS stimulation of macrophages requires TPL-2 phosphorylation on S400, in addition to its release from NF-κB1 p105. Oncogenic C-terminal truncations of TPL-2 that remove S400 could promote its transforming potential by eliminating this critical control step.

scholarly journals p38α Isoform Mxi2 Binds to Extracellular Signal-Regulated Kinase 1 and 2 Mitogen-Activated Protein Kinase and Regulates Its Nuclear Activity by Sustaining Its Phosphorylation Levels

2003 ◽  
Vol 23 (9) ◽  
pp. 3079-3090 ◽  
Author(s):  
Victoria Sanz-Moreno ◽  
Berta Casar ◽  
Piero Crespo
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Kinase Activity ◽  
Ectopic Expression ◽  
Mitogen Activated Protein Kinase ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Nuclear Events ◽  
Epidermal Growth ◽  
Splice Isoform

ABSTRACT Mxi2 is a p38α splice isoform that is distinctively activated by mitogenic stimuli. Here we show that Mxi2 immunoprecipitates carry a kinase activity that is persistently activated by epidermal growth factor in a fashion regulated by Ras, Raf, and MEK. We demonstrate that this kinase activity can be attributed not to Mxi2 but rather to extracellular signal-regulated kinases 1 and 2 (ERK1/2), which coimmunoprecipitated with Mxi2 both by ectopic expression and in a physiological environment like the kidney. Furthermore, we provide evidence that Mxi2-ERK interaction has profound effects on ERK function, demonstrating that Mxi2 prolongs the duration of the ERK signal by sustaining its phosphorylation levels. Interestingly, we show that the effects of Mxi2 on ERK are restricted to nuclear events. Mxi2 potently up-regulates ERK-mediated activation of the transcription factors Elk1 and HIF1α but has no effect on the activity of ERK cytoplasmic substrates RSK2 and cPLA2, induced by epidermal growth factor or by MEK. Overall, our findings point to Mxi2 as a unique member of the p38 family that may have an unprecedented role in the regulation of the functions of ERK mitogen-activated protein kinases.

scholarly journals Advances in anti-BRAF therapies for lung cancer

2021 ◽  
Author(s):  
Giandomenico Roviello ◽  
Alberto D’Angelo ◽  
Marianna Sirico ◽  
Matteo Pittacolo ◽  
Felipe Umpierre Conter ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Critical Role ◽  
Cellular Growth ◽  
Mitogen Activated Protein Kinase ◽  
Western World ◽  
Braf Mutations ◽  
Raf Kinase ◽  
Proliferation And Differentiation ◽  
Mitogen Activated Protein ◽  
Causes Of Mortality

SummaryNon-small cell lung cancer (NSCLC) is one of the most frequent causes of mortality in the western world. v-raf murine sarcoma viral oncogene homolog B (BRAF) is a member of the Raf kinase family and plays a critical role in cellular growth, proliferation, and differentiation through the mitogen-activated protein kinase pathway. The incidence of BRAF mutations in NSCLC is low, accounting for 0–3% of all cases of lung cancer. Given the results obtained in metastatic melanoma, several studies have reported the efficacy of anti-BRAF therapies in NSCLC treatment. In this review, we describe changes in the landscape of BRAF-mutated lung cancer treatment and analyze insights from major clinical trials in the context of future therapeutic prospects.

scholarly journals BRAF: A Two-Faced Janus

Cells ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2549
Author(s):  
Pasquale Pisapia ◽  
Francesco Pepe ◽  
Antonino Iaccarino ◽  
Roberta Sgariglia ◽  
Mariantonia Nacchio ◽  
...  
Keyword(s):  
Braf Mutations ◽  
Extracellular Signal Regulated Kinase ◽  
Oncogenic Mutations ◽  
Extracellular Signal ◽  
Therapeutic Decisions ◽  
Protein Map ◽  
Thyroid Papillary ◽  
Mitogen Activated Protein ◽  
Murine Sarcoma ◽  
Viral Oncogene Homolog

Gain-of-function of V-Raf Murine Sarcoma Viral Oncogene Homolog B (BRAF) is one of the most frequent oncogenic mutations in numerous cancers, including thyroid papillary carcinoma, melanoma, colon, and lung carcinomas, and to a lesser extent, ovarian and glioblastoma multiforme. This mutation aberrantly activates the mitogen-activated protein (MAP) kinase extracellular signal-regulated kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathway, thereby eliciting metastatic processes. The relevance of BRAF mutations stems from its prognostic value and, equally important, from its relevant therapeutic utility as an actionable target for personalized treatment. Here, we discuss the double facets of BRAF. In particular, we argue the need to implement diagnostic molecular algorithms that are able to detect this biomarker in order to streamline and refine diagnostic and therapeutic decisions.

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